Some nasal assemblies used in the treatment of SDB are designed for insertion into the nasal passages of the patient. Air or other breathable gas is supplied by a blower and passed along a flexible conduit to the nasal assembly.
The nasal assembly generally includes a relatively rigid shell, e.g., a frame, and a pair of nozzles (which may be in the form of nasal pillows, nasal prongs, cannula, or nasal puffs) that are mounted on the rigid shell and structured to be inserted into the nasal passages of the patient. The nozzles are usually held in place using a headgear assembly, the relatively rigid shell and headgear assembly being joined using some form of connector.
One form of known nasal assembly is described in U.S. Pat. No. 4,782,832 (Trimble et al.). Trimble discloses a nasal puff assembly 20 that includes a nasal puff 22 adapted to be worn adjacent the nose of a patient, together with a harness assembly 24 adapted to be worn over the head of the patient. The harness assembly 24 is designed to operatively hold puff 22 adjacent and partially within the nasal passages of the patient.
The puff 22 is in the form of a generally Y-shaped rigid hollow plenum chamber 28 together with a pair of laterally spaced apart nares elements 30. Adjustability of the nares elements 30 may be provided by rotatably mounting the elements 30 to the plenum chamber 28 and mounting the elements 30 in slots permitting selective lateral positioning of the elements 30 with respect to each other. Also, the harness assembly 24 may be adjusted to adjust the fit and seal of the nares elements 30 during use. That is, the force required to maintain a sufficient seal is directly associated with the force required to maintain a desired fit. Thus, adjustment of the fit or stability of the nasal assembly directly affects the seal, which can adversely affect patient comfort.
Other examples of nasal pillows or cannula mounted to rigid shells are disclosed in U.S. Pat. Nos. 5,724,965 and 6,431,172.
A nasal mask assembly manufactured by Viasys, i.e., SPIRITUS™, includes a plenum chamber with a pair of adjacent or laterally spaced nares elements. A harness assembly is engaged with the plenum chamber to adjust the fit and seal of the nares elements during use. Similar to Trimble, adjustment of the fit or stability of the nasal assembly directly affects the seal, which can adversely affect patient comfort.
A nasal mask assembly manufactured by InnoMed, i.e., NASAL AIRE™, includes a plenum chamber with a pair of adjacent or laterally spaced nares elements. The nares elements are structured to engage within the mucosal surfaces or internal passages of the patient's nose to maintain the nasal mask assembly on the patient's face and to provide a seal. See, e.g., U.S. Pat. No. 5,533,506.
A nasal mask assembly manufactured by Stevenson Industries (see U.S. Pat. No. 6,012,455), i.e., CPAP-PRO™, includes a dental anchor, a platform, and air supply tubes having nasal pads, wherein the platform supports the air supply tubes. The dental anchor is sized to be engaged between the teeth in the patient's mouth so as to retain the assembly in place.
PCT Application Publication No. WO 00/13751 discloses a device that includes gas delivery elements positioned into engagement with the patient's nose by a mouthpiece fitted to the patient's teeth.
A common problem with known nasal assemblies, such as those discussed above, is patient comfort. For example, the prongs tend to irritate the patient's nose due to the tension applied by the headgear assembly that pulls the rigid shell and prongs towards the patient's nose.
Another problem is achievement of a sealing fit with the patient's nasal passages without sacrificing patient comfort.
Another problem is irritation of the inside of the patient's nostrils caused by contact with the prongs, e.g., an edge thereof.
Another problem is irritation of the inside of the patient's nostrils caused by air jetting (air flow irritation) from the prongs.
Another problem is adjustment of the nasal assemblies relative to the nose and/or head of the patient so as to accommodate various shapes and angles of patient's noses.
Still another problem is the direct association between sealing and stability forces that can affect patient comfort.